1. Field of the Invention
This invention relates to a radio remote control system for a model drive unit such as a model plane or the like which is adapted to output a transmission signal representing a control data from a transmission section including a radio transmitter and receive the signal at a receiving section including a radio receiver mounted on a controlled object such as a model car, a model plane or the like to carry out remote control of variable sections of the controlled object, and more particularly to a radio remote control system which is improved to replace one controlled object corresponding to one transmission section with one of a plurality of controlled objects every time to delete adjustment operation due to a difference between individual controlled objects which has been conventionally required in connection with a trim data every control operation for finely adjusting relationships between a control data from a transmission section and the amounts of displacement of variable sections of a controlled object corresponding to the control data.
2. Description of the Prior Art
A conventional radio remote control system of this type includes a transmission section which is typically constructed in such a manner as shown in FIG. 3.
More particularly. in the conventional control system, variable resistors 2 and 3 operationally connected to one control lever 1 on a control panel and a variable resistor 4 operationally connected to another control lever 1' on the control panel are separately arranged with respect to channels respectively allocated to variable sections of a controlled object. The variable resistors 2, 3 and 4 each are connected at one end thereof to a common power supply V and at the other end thereof to the grounds to form a bleeder. Sliders 2a, 3a and 4a of the resistors 2, 3 and 4 are connected to one input terminals of voltage adding circuits 5, 6 and 7, respectively. Thus, the variable resistors 2, 3 and 4 constitute main control voltage generating circuits 2A, 3A and 4A, respectively.
Now, the variable sections concerned with control operation will be exemplified. When a controlled object is, for example, a model plane, the variable resistor 2 allocated to a first channel is in charge of control of an aileron (aileron of main wing), the variable resistor 3 for a second channel is in charge of control of an elevator (aileron of horizontal tail) and the variable resistor 4 for a third channel is in charge of control of a throttle.
The two control lever 1 and 1' on the control panel are generally operable every direction, and the variable resistors 2, 3 and 4 are separately operated corresponding to the operation of the control levers 1 and 1' every displacement region of the levers.
In addition, the conventional radio remote control system includes trim controllers 8, 9 and 10 provided corresponding to the respective displacement regions of the two control levers 1 and 1' and variable resistors 11, 12 and 13 arranged on the control panel in a manner to be operationally connected to the trim controllers 8, 9 and 10, respectively. The variable resistors 11, 12 and 13 each are connected at one end thereof to the common power supply V and at the other end thereof to the grounds. Sliders 11a, 12a and 13a of the resistors 11, 12 and 13 are connected to the other input terminals of the voltage adding circuits 5, 6 and 7, respectively.
Thus, the variable resistors 11, 12 and 13 constitute trim control voltage generating circuits 11A, 12A and 13A, respectively.
The voltage adding circuits 5, 6 and 7 are connected at output terminals thereof to input terminals of a multiplexer 14, respectively, which is connected in turn at an output terminal thereof to a subsequent analog to digital converter 15. The analog to digital converter 15 is then connected at an output terminal thereof through a data bus 15a comprising a plurality of wires and led out therefrom to an input terminal of a parallel/serial conversion circuit 16, which is connected in turn at an output terminal thereof through a pair of data lines 16a to an input terminal of a radio transmitter 17 which is provided with a transmitting antenna 17a.
Also connected to the parallel/serial conversion circuit 16 are a clock pulse oscillating circuit 18 and an address counter 19. The counter 19 is connected at an output terminal thereof to an address terminal of the multiplexer 14 through an address bus 19a comprising a plurality of wires and extending therebetween.
In the conventional control system constructed as described above, the operation of the two control levers 1 and 1' in the respective displacement regions for control causes the sliders 2a, 3a and 4a of the variable resistors 2, 3 and 4 to be slided, so that main control voltages E1, E2 and E3 corresponding to the amounts of displacement of the control levers 1 and 1' may appear at the sliders 2a, 3a and 4a, which are then concurrently supplied through the voltage adding circuits 5, 6 and 7 to the input terminals of the multiplexer 14, respectively.
Now, supposing that an address of the multiplexer 14 designates its first input terminal, the main control voltage E1 supplied to the first input terminal of the multiplexer 14 through the voltage adding circuit 5 is selected and appears at the output terminal of the multiplexer. The voltage E1 is then supplied to the analog to digital converter 15 and converted to a parallel digital code therein, which are supplied in the form of a main control voltage code C1 representing the main control voltage E1 through the data bus 15a to the parallel/serial conversion circuit 16. The circuit 16 receiving the parallel main control voltage code C1 assembles the code C1 into an ordinal transmission code and converts the transmission code into a serial transmission code C2 of a bit rate defined by a frequency of a clock pulse S1 from the clock pulse oscillating circuit 18. The so-converted transmission code C2 is then transferred through the data lines 16 to the radio transmitter 17, which transmits the code C2 to a radio receiver in a receiving section (not shown).
The parallel/serial conversion circuit 16 supplies a completion code C3 to the address counter 19 to carry out stepping of the code when it completes transfer of the transmission code C2 corresponding to one channel of the main control voltage code C1 derived from the main control voltage E1.
Then, the address counter 19 feeds a subsequent address code C4 through an address bus 19a to an address terminal of the multiplexer 14, so that the multiplexer 14 selects the main control voltage E2 supplied to the second input terminal thereof in response thereto and supplies it through the output terminal thereof to the analog to digital converter 15.
Thus, every time when the transmission code C2 for the first channel representing one main control voltage is transmitted, the stepping of the address code C4 to the multiplexer 14 is carried out to select a subsequent main control voltage, so that the transmission code C2 for the second channel representing it may be transmitted. In a similar manner, a control data indicated by the amount of displacement of each of the control lever 1 and 1' in its displacement region is subjected to time-sharing transmission for each of the channels allocated to the respective variable sections, and then the receiving section which has received it by means of a radio receiver positionally changes each of the variable sections corresponding to the amount of displacement of each of the control levers 1 and 1' to carry out remote control of the controlled object.
In the conventional control system described above, trimming or trim adjustment is required to coincide the substantially neutral position of each of the variable sections of the controlled object in an actual driving state with the mechanical neutral position of each of the control levers 1 and 1' on the transmission section side in view of a difference in characteristics or the like between individual controlled objects. In such operation, when an operator separately operates the trim controllers 8, 9 and 10 to move the sliders 11a, 12a and 13a of the variable resistors 11, 12 and 13, trim control voltages e1, e2 and e3 corresponding to the amounts of displacement of the trim controllers 8, 9 and 10 appear at the sliders 11a, 12a and 13a, which are then supplied to the one input terminals of the voltage adding circuits 5, 6 and 7, respectively. The voltage adding circuits 5, 6 and 7 superposedly add the trim control voltages e1, e2 and e3 to the main control voltages E1, E2 and E3 supplied to the other input terminals thereof in an analog manner to obtain control voltages (E1+e1), (E2+e2) and (E3+e3) and then supply the so-obtained control voltages to the input terminals of the multiplexer 14, respectively.
The control voltages alternatively selected by the multiplexer 14 are converted into parallel control voltage codes C0 by means of the analog to digital converter 15. A signal treatment of the control voltages in the parallel/serial conversion circuit 16 and the subsequent elements is carried out in substantially the same manner as that of the main control voltage codes C1 described above.
Thus, the operation of the trim controllers 8, 9 and 10 at the transmission section for adjusting the trim control voltages e1, e2 and e3 causes control codes representing the substantially neutral positions of the variable sections of the controlled object to be transmitted from the receiving section to the transmission section while keeping each of the control levers 1 and 1' of the transmission section at its mechanically neutral position.
The conventional radio remote control system described above is convenient in that when only one controlled object provided with one receiving section corresponding to one transmission section is solely or exclusively specified, it is merely required to stationarily store the trim control voltages el, e2 and e3 of the variable sections determined depending upon the specific characteristics of the sole controlled object as the mechanical positions of the trim controllers 8, 9 and 10 of the transmission section in the trim controllers. However, it has been recently desired to correspond a plurality of controlled objects to one transmission section in a manner to be replaced one by one with respect to the transmission section so that satisfied applicability to various controlled objects may be met and such a control system of a high grade may be manufactured at a low cost. The replacement of a controlled object corresponding to one transmission section with another controlled object for such a purpose requires to change the positions of the trim controllers 8, 9 and 10 depending upon the specific characteristics of each of the controlled objects every replacement, resulting in the trimming or trim adjustment being highly troublesome.